a. Field of the Invention
This invention relates generally to lens holders and more particularly to devices for temporarily attaching a lens to a pair of spectacle frames for measuring and testing purposes.
b. Prior Art
Ophthalmic practitioners utilize many specialized testing devices in the category of lens holders. One such device is the "Janelli Clip" which basically includes a pair of lens holders with cylindrical channels for eye pieces that form a number of test lens wells. The ophthalmic practitioner places one or more test lenses in the lens wells to test a prescription or to demonstrate a change in prescription or for other purposes.
Another piece of equipment used by ophthalmic practitioners is a clip-on device which tests for bifocal line placement in a bifocal correction lens. One such apparatus includes a pair of simulated opaque bifocal shaped members positioned over the lens sockets of an empty pair of spectacle frames by a pair of plastic spring clips. The height of each of the bifocal type lenses may be then adjusted by the practitioner or by the patient until the patient is satisfied with its position. The position of the two test lenses is then noted so that the bifocal line of the permanent lenses will be correctly positioned.
There are also a number of corrective devices, similar to the above mentioned bifocal test clip, but not used for testing, that can be attached to an existing pair of eyeglasses to supplement or modify the refractive property of the permanent lenses. These devices typically include relatively small lenses that are adjustably or removably attached to the frames of the glasses, and may be either prescribed by the refractionist or may be purchased by the consumer in an over-the-counter situation. Examples of these devices are found in U.S. Pat. Nos. 1,661,967 of J. Savoie, 1,949,449 of F. Broomfield, 2,006,645 of C. Masters, 2,384,233 of A. Bishop, 2,842,029 of A. Roth and 3,446,548 of W. Rummel, et al.
Besides measuring and testing lens prescriptions, an ophthalmic practitioner frequently desires to show a patient the appearance of frames, without lenses, on his or her face. Often, the patient cannot see well enough to view him or herself in a mirror without corrective lenses. It is an object of this invention to provide an ophthalmic device which can temporarily attach a test lens to a pair of spectacle frames so that a patient can see what the frames look like as he or she is wearing them.
Another object of the invention is to provide a combination device which can be used both to hold test lenses to a pair of spectacle frames with and without a prescription lens and which can be used to determine the correct placement of the bifocal line of a permanent eyeglass lens.
Another object of the invention is to demonstrate a new prescription in a spectacle frame or to show the change in prescription over the patient's old prescription.